A certain salesman, called Mark O.V. delivers his goods to three cities: C1, C2, & C3, staying only for one day at a time in each of them. His stay in C1 is always followed by going next to C2.
If he delivers in either C2 or C3 he is thrice as likely to continue to C1, than to the other city.

Provide your estimate of the number of working days in each of the cities within a period of 12,000 working days.